Question

Write the IUPAC name of $ C{H_3}C{H_2}COOH $
(A) Ethyl formic acid
(B) Ethyl carboxylic acid
(C) Ethane methanoic acid
(D) Propanoic acid

Answer 1

Hint: IUPAC expands as International Union of Pure and Applied Chemistry. IUPAC nomenclature is the method of naming the organic compounds which are recommended by the IUPAC, i.e, International Union of Pure and Applied Chemistry.

Complete step-by-step answer
First of all, we have to know basic rules of the IUPAC nomenclature:
(i) First, we have to find out the functional group, having the highest preference. The carboxylic acid group has the highest preference.
(ii) Then, we have to find the longest chain in the organic molecule containing the functional group which has the highest preference in that molecule, the suffix of the higher preference will be the suffix of the molecule.
(iii) The number of the carbons in the longest carbon chain will be written before the suffix.
(iv) If there is presence of some substituted carbon chains or any other functional groups in the molecule, then they are named as their prefix, the functional groups present and the alkyl groups are present.
So, from the basic rules of the IUPAC nomenclature, we try to find out the naming of the compound:
The functional group contains the organic molecule is Carboxylic acid and the longest chain of the carbon is of three carbons. So, the suffix will be –oic acid and the number of the carbons in the molecule is three. So, the prefix will be Propan-.
The chemical name of the $ C{H_3}C{H_2}COOH $ is Propanoic Acid.
Hence, the name of the molecule $ C{H_3}C{H_2}COOH $ will be Propanoic acid.
The correct option is (D) Propanoic acid.

Note:
There are two naming of any molecules, Common names and IUPAC nomenclature. Common names are the names which are commonly used. The common name of the Propanoic acid is Propionic acid.